title: Contribution of IL-6 to the Hsp72, Hsp25, and alphaB-crystallin [corrected] responses to inflammation and exercise training in mouse skeletal and cardiac muscle.
abstract: The heat shock proteins (Hsps) Hsp72, Hsp25, and alphaB-crystallin (alphaB C) [corrected]may protect tissues during exercise and/or inflammatory insults; however, no studies have investigated whether exercise training increases both basal and inflammation-induced expression of these Hsps in skeletal or cardiac muscle. IL-6 is produced by muscle during both exercise and inflammation and has been shown to modulate Hsp expression. These studies tested the hypothesis that voluntary wheel running (RW) increases basal and inflammation-induced Hsp72, Hsp25, and alphaB C [corrected] protein through an IL-6-dependent mechanism. We compared Hsp72, Hsp25, alphaB C, [corrected] and IL-6 protein levels 4 h after systemic inflammation induced by lipopolysaccharide (LPS) in skeletal and cardiac muscles of wild-type (IL-6(+/+)) and IL-6 deficient (IL-6(-/-)) mice after 2 wk of RW or normal cage activity (Sed). LPS significantly increased skeletal Hsp72 and Hsp25 relative to saline in Sed IL-6(+/+), but not IL-6(-/-) mice. LPS increased Hsp72 relative to saline in Sed IL-6(+/+) cardiac muscle. RW increased basal Hsp72, Hsp25, and alphaB C [corrected] in skeletal muscle in IL-6(+/+) and IL-6(-/-) mice. However, LPS was not associated with increases in any Hsp in RW IL-6(+/+) or IL-6(-/-) mice. LPS increased IL-6 protein in skeletal muscle and plasma in Sed and RW groups, with a significantly greater response in RW. The major results provide the first in vivo evidence that the absence of IL-6 is associated with reduced skeletal muscle Hsp72 and Hsp25 responses to LPS, but that IL-6 is not required for exercise-induced Hsp upregulation in skeletal or cardiac muscle.
authors.affiliation: Department of Kinesiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. khuey@illinois.edu
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Huey
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Meador
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D050884:HSP72 Heat-Shock Proteins / Q000096:biosynthesis*; D006321:Heart / Q000502:physiology; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D015850:Interleukin-6 / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018832:Molecular Chaperones; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D010805:Physical Conditioning, Animal / Q000502:physiology; D012420:Running / Q000502:physiology; D038201:alpha-Crystallins / Q000096:biosynthesis*; D038204:beta-Crystallins / Q000096:biosynthesis*
chemical_list: D050884:HSP72 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; D015850:Interleukin-6; D008070:Lipopolysaccharides; D018832:Molecular Chaperones; D009124:Muscle Proteins; D009363:Neoplasm Proteins; D038201:alpha-Crystallins; D038204:beta-Crystallins